Cooperative Catalytic Activation of Si-H Bonds by a Polar Ru-S Bond: Regioselective Low-Temperature C-H Silylation of Indoles under Neutral Conditions by a Friedel-Crafts Mechanism
Cooperative Catalytic Activation of Si-H Bonds by a Polar Ru-S Bond: Regioselective Low-Temperature C-H Silylation of Indoles under Neutral Conditions by a Friedel-Crafts Mechanism
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DOI：
10.1021/ja111483r
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发表时间：
2011-03-16
影响因子：
15
通讯作者：
Tatsumi, Kazuyuki
中科院分区：
文献类型：
--
作者：
Klare, Hendrik F. T.;Oestreich, Martin;Tatsumi, Kazuyuki
合并协同Si-H键活化和亲电芳香取代为电子而非常规空间控制下的C-3-选择性吲哚C-H官能化铺平了道路。Si-H键被配位不饱和的阳离子钌（II）络合物的Ru-S键异裂，形成硫稳定的硅亲电体。假设随后的Friedel-Crafts型过程的Wheland中间体被硫原子去质子化，不需要添加碱。整个催化过程在低温下无溶剂进行，仅释放出氢气。
Merging cooperative Si-H bond activation and electrophilic aromatic substitution paves the way for C-3-selective indole C-H functionalization under electronic and not conventional steric control. The Si-H bond is heterolytically split by the Ru-S bond of a coordinatively unsaturated cationic ruthenium(II) complex, forming a sulfur-stabilized silicon electrophile. The Wheland intermediate of the subsequent Friedel-Crafts-type process is assumed to be deprotonated by the sulfur atom, no added base required. The overall catalysis proceeds without solvent at low temperature, only liberating dihydrogen.